Corn plants are typically planted in rows spaced a predetermined distance apart. Harvesting units of corn headers are spaced a corresponding distance apart so as to be capable of following the rows while inducting the corn plants. When entering and moving through a stand of corn, the harvesting elements of the harvesting units of the header are preceded by row dividers that separate the adjacent rows of plants for harvesting by the respective harvesting units. The harvesting units are configured and operable for receiving the stalks of the corn plants of the respective rows in succession, and removing the full or intact ears of corn, for conveying by other apparatus from the header to processing apparatus within the harvesting machine. Typical harvesting elements of a harvesting unit are located adjacent to the rear of the row dividers, bounding the stalk receiving channel, also referred to as the picking channel or gap. The harvesting elements can comprise a variety of devices operable for harvesting the corn ears from the stalks, including fore to aft moving gathering chains having teeth operable for carrying the corn ears rearwardly to the conveying apparatus of the header. The elements can also include fore and aft extending picking or snapping rolls located in association with the deck plates, which are also referred to as, or carry, stripper bars or plates also bounding the channel or gap. In a typical configuration, the gathering chains are located above the deck or stripper plates and the snapping rolls are located below. The snapping rolls are rotatable for pulling the corn stalk downwardly, through rearwardly moving fingers of the gathering chains, to bring the ears to bear against the top edges of the deck plates so as to be detached from the stalks thereby. The detached ears are then carried toward the rear of the header by the gathering chains for conveying by other apparatus into the harvesting machine, while the collapsed stalks are left on the field.
The typical harvesting unit includes a frame supporting the deck plates in spaced relation bounding the stalk receiving channels. The deck plates can be spaced a variety of distances apart. For instance, the spacing can be large such that a gap or space exists between the adjacent edge of the deck plate and the side of the stalks, on one or both sides of the stalks. Or, the spacing can be smaller, such that edges of the deck plates contact the sides and even pinch or squeeze the stalks. In the first instance, if the gap or space is large, an advantage is that more of the remaining plant residue or trash, e.g., leaves, stalks, husks, can fall through the enlarged channel so as not to build up in the harvesting unit, and not be conveyed into the harvester. But, a disadvantage is that the upper ends of the stalks are less supported, and may tend to whip around more as the lower ends are collapsed into the ground, raising the potential that some stalks will be broken and ears will be lost. Corn ears may also tend to get pulled down between the edges of the deck plates such that kernels are detached and lost. Smaller ears may also get caught between the opposing deck plates and cause trash buildup. In the second instance, if the pinch force is too great, stalks may get caught between the deck plates and bunch up in the channel and be damaged or broken such that, again, ears are lost, and more trash may be retained and carried by the gathering chains into the header.
As proposed solutions to the problems set forth above, it is known for the deck plates to be movable laterally, e.g., using an actuator such as a hydraulic cylinder, to allow adjusting the width of the stalk receiving channel, from the operator cab based on observations and/or operator preferences, mainly, based on estimates of stalk diameter, and/or to achieve good stalk flow into the harvesting units. However, if the operator lacks experience, or is inattentive, the channel width can be too big or small, resulting in the above listed problems. It is also known for the deck plates to be spring mounted to bring the edges of the deck plates to bear against the largest diameter stalks currently located therein while exerting a pinching force. This provides a degree of automatic adjustment and can eliminate gaps or spaces between the edges of the deck plates and the stalks. However, this force will be strictly a function of the spring constant and the degree of compression or extension thereof, if working properly. As another problem, sugars from the stalks and dust adhered thereby to the plates and surrounding structure so as to reduce and even overcome the spring forces and inhibit free lateral adjusting movements of the plates, such that they can stick open too widely or too narrowly so as to undesirably affect the pinching force, disrupt stalk flow and ear removal, and the like.
In some instances, such as when entering a stand of corn, it would be advantageous to have an ability to increase the deck plate spacing to open the stalk receiving channels to facilitate aligning the harvesting units with the rows and to reduce occurrence of laying or pushing the stalks over. Then, after good alignment is achieved, it would be advantageous to reduce the width of the channels to a size that best fits the stalk size of the corn being harvested and to exert a desired pinching force against the stalks for controlling kernel loss and the like.
Thus, what is sought is a manner of controlling deck plate positioning and stalk pinching force if utilized, which overcomes one or more of the shortcomings and problems, and provides one or more of the advantages, set forth above.